Reciprocal microwave phase shifter having a plurality of longitudinal and transverse energizing conductors passing through the ferrimagnetic material

ABSTRACT

A RECIPROCAL MICROWAVE PHASE SHIFTER IS DESCRIBED WHEREIN A FERRIMAGNETIC MATERIAL IS DISPOSED ALONG AN ELECTROMAGNETIC ENERGY GUIDING PATH. THE FERRIMAGNETIC MATERIAL IS PROVIDED WITH LONGITUDINAL AND TRANSVERSE ORIENTED BORES TO ACCOMMODATE CORRESPONDINGLY ORIENTED CONDUCTORS WHICH ARE SO INTERCONNECTED AND ENERGIZED TO FORM THE DESIRED RECIPROCAL PHASE SHIFTING PERFORMANCE.

Jan. 12, 1971 NAOYUKl S W RA 'ETAL 3,555,463

RECIPROCAL MICROWAVE PHASE SHIFTER HAVING A PLURALITY OF LONGITUDINALAND TRANSVERSE 'ENERGIZING CONDUCTORS PASSING THROUGH THE FERRIMAGNETICMATERIAL FiledOct. 17 1968 w 2 Sheets-Sheet 1 7 9/01? APT MFM5 125 F l G4 INVENTORS NAOYUKI OGAS'AWARA TAOA SHI HASHIMOTO MITSURU sue/e HIROMINOMURA Arrok Y5 Jan. 12; 1971 NAOYUKl QGASAWARA ET AL 3,555,463

RECIPROCAL MICROWAVE PHASE SHIFTER HAVING A PLURALITY OF LONGITUDINALAND TRANSVERSE ENERGIZING CONDUCTORS PASSING THROUGH THE FERRIMAGNETICMATERIAL 2 Sheets-Sheet 2 Filed cm. 17, 1968 INVENTORS NAOYUK/ OGASAWARATADASH/ HASH/M070 YMITSURU suals HIROMI NOMURA ATTOQNEYS FlG.6c

United States Patent Oce Patented Jan. 12, 1971 U.S. Cl. 333-31 11Claims ABSTRACT OF THE DISCLOSURE A reciprocal microwave phase shifteris described wherein a ferrimagnetic material is disposed along anelectromagnetic energy guiding path. The ferrimagnetic material isprovided with longitudinal and transverse oriented bores to accommodatecorrespondingly oriented conductors which are so interconnected andenergized to form the desired reciprocal phase shifting performance.

This invention relates to a reciprocal microwave phase shifter forcontrolling the phase of the electromagnetic waves in the microwaveband.

Conventional microwave phase shifters are mostly of the nonreciprocaltype. Reciprocal phase shifters are known but have not been fullysatisfactory for some applications. One of such applications is the useof a plurality of electrically controllable phase shifters forcontrolling thephase of the electromagnetic waves at the plane of aradar antenna array. It has been known that this kind of application isthe most desirable in effecting high speed scanning of the radar beam.High speed scanning was made feasible by appearance of a nonreciprocalmicrowave phase shifter comprising a waveguide and a member which ismade of ferrite or other ferrimagnetic material having rectangularmagnetization characteristics and which is disposed in the waveguide.This phase shifter is excellent because of its simplicity ofconstruction, its ability to operate at a high speed, and its capabilityof withstanding the high powers used in the radar transmitter. Such anon-reciprocal phase shifter, however, is not desirable because it mustbe interswitched on turning the radar equipment from the transmittingoperation to the receiving operation and vice versa and the resultingcomplexity of the equipment. A reciprocal phase shifter completelyeliminates the last-mentioned demerits but has not yet been put topractical use because it has still had certain defects such as a poorstanding wave ratio, a large insertion loss, and requires complicatedcircuit if the maximum amount of phase shift is to be obtained. Itshould be noted here that microwave means electromagnetic waves that canbe propagated by a waveguide or by a pair of strip conductors.

It is therefore an object of this invention to provide a reciprocalmicrowave phase shifter which does not deteriorate the standing waveratio.

It is another object of the invention to provide a reciprocal microwavephase shifter which has little insertion loss.

It is still another object of the invention to provide a reciprocalmicrowave phase shifter by which the maximum phase shift is attainedwithout any complicated circuit.

According to this invention there is provided a reciprocal microwavephase shifter comprising a path for guiding the electromagnetic energy,a member of ferrimagnetic material having rectangular magneticcharacteristics and which is disposed along the longitudinal axis ofsaid path, a first set of conductors disposed transverse to saidlongitudinal axis, a second set of conductors disposed substantiallyparallel to said longitudinal axis, and means for selectively energizingone of said first set and said second set of conductors.

Now the invention will be described with reference to the accompanyingdrawings, in which:

FIG. 1 is a perspective view of a conventional nonreciprocal microwavephase shifter;

FIG. 2 is a similar view of another phase shifter of the kind;

FIG. 3 (a) is a similar view of a conventional reciprocal microwavephase shifter;

FIG. 3(b) shows the manner of connecting the conductors of the phaseshifter illustrated in FIG. 3(a); and

FIGS. 4, 5 and 6 are perspective views of certain embodiments of thisinvention.

Referring to FIG. 1, a conventional non-reciprocal microwave phaseshifter comprises a rectangular wave guide and a ferrimagnetic memberdisposed along the longitudinal axis of the waveguide. The ferrimagneticmember is made of ferrimagnetic material having rectangularmagnetization characteristics and is formed into a generally rectangularcylinder having a hollow inner space of the generally rectangular prismshape. The phase shifter further comprises a conductor generallyextended through the hollow inner space. Electric current caused to flowthrough the conductor in the sense shown by arrow heads creates withinthe body of the ferrimagnetic member closed magnetic lines of forcesillustrated by a broken line having arrow heads. The electromagneticwave travelling through the waveguide in the fundamental mode (TE mode)in one sense is thereby polarized into positive circularly polarizedwave (whose electric vector rotates in the same sense as the spinmagnetic moment of the ferrimagnetic material), while theelectromagnetic wave travelling through the waveguide in the reversedsense is polarized into negative circularly polarized wave (whoseelectric vector rotates in the sense opposite to the sense of rotationof the spin magnetic moment). The arrangement thus serevs as anon-reciprocal microwave phase shifter.

Referring to FIG. 2, another microwave phase shifter comprises aferrimagnetic member which is different from the corresponding member inthe phase shifter shown in FIG. 1 in that the member of the example ofFIG. 2 is composed of two separate parts or elements. Each ferrimagneticelement is substantially identical to the ferrimagnetic member describedwith reference to FIG. 1 and is accompanied by a conductor. Whenelectric currents are caused to flow through the respective conductorsin the senses shown by broken-line arrows, the operation is similar tothat of the example depicted in FIG. 1. When electric currents arecaused to flow in the senses illustrated by solid-line arrows, it hasempirically been confirmed that the arrangement of FIG. 2 displaysreciprocal characteristics or, more particularly, propagates theelectromagnetic wave in the fundamental mode as though the ferrimagneticmember were not in the magnetized state. It is believed that thisphenomenon results because the phase shifts caused by the respectiveferrimagnetic elements in one and the other sense cancel each other andbecause no non-reciprocal phase shift is accordingly observed from theoutside.

Referring to FIG. 3(a), a conventional reciprocal phase shifter is shownhaving generally similar components as the phase shifters of FIGS. 1 and2, except that in the phase shifter of FIG. 3(a) a pair of conductorsA-A' and B-B' are wound around a half of the arrangement. Moreparticularly, conductor portions lying on the central plane of thewaveguide are substantially perpendicular to the longitudinal axis ofthe waveguide and thread through the waveguide and the ferrimagneticmember. The remaining portions run outside the Waveguide along the wallsthereof.

Referring to FIGS. 3(a) and (b), the arrangement of FIG. 3(a) showsreciprocal phase shift when connection of the conductors AA' and B-B isinterswitched between the S connection shown in FIG. 3(b)(i) and the Pconnection illustrated in FIG. 3(b)(ii). With this arrangement, themaximum phase shift is attained when the ferrimagnetic member is broughtfrom the entirely demagnetized state to the fully magnetized state orvice versa. When switched to the S connection, the arrangement providesa phase shift whose amount is smaller than the amount attainable byinter-switching between the P connection energization and the entirelydemagnetized state. With the S connection, the arrangement is apt todeteriorate the standing wave ratio and to increase the insertion loss.Incidentally, demagnetization of the ferrimagnetic member, if to beeffected at a high speed, requires a complicated circuit.

Turning now to FIG. 4, a first embodiment of this invention comprises arectangular waveguide 11 and a ferrimagnetic member composed of twoferrimagnetic elements 12 and 12'. Each ferrimagnetic element is made offerrimagnetic material having rectangular magnetic characteristics andis formed into a generally rectangular cylinder having a hollow innerspace of the generally rectangular prism shape. The ferrimagneticelements 12 and 12 are disposed within the waveguide 11 along thelongitudinal axis thereof on both sides of a plane passing through thecenter lines of the broad walls of the guide 11. A set of opposite wallsof each ferrimagnetic element is in the proximity of the broad walls.The embodiment further comprises a set of transverse conductors 13penetrating the narrow walls of the waveguide 11 and the other set ofwalls of the individual ferrimagnetic elements 12 and 12'. Theseconductors 13 are connected at the outside of the waveguide 11 in themanner shown and provided with a D.C. power source 14. The embodimentstill further comprises a set of longitudinal conductors 15 and 15generally extended through the spaces of the ferrimagnetic elements 12and 12, respectively, and brought out of the waveguide 11. Theselongitudinal conductors 15 and 15 are provided with D.C. power sources16 and 16, respectively. The D.C. power source 14 supplies a D.C.control pulse to each of the transverse conductors 13 each time a switch17 is closed. Likewise, the D.C. power sources 16 and 16 supply D.C.control pulses to the longitudinal conductors 15 and 15, respectively,every time ganged switches 18 and 18 are closed.

When the transverse conductors 13 are energized by a D.C. control pulse,the phase shifter is brought into the same state as the conventionalreciprocal phase shifter of FIG. 3(a) with the P connection. Theelectromagnetic wave travelling through the phase shifter thereforeundergoes reciprocal phase shift of a certain amount as compared withthe phase of the wave propagated in the fundamental mode. When thetransverse conductors 13 are deenergized and the longitudinal conductors15 and 15 are instead energized by a pair of D.C. control ulses flowingthrough the respective conductors 15 and 15', the phase shifter isbrought into the same state as the conventional non-reciprocal phaseshifter of FIG. 2 with the conductors supplied with electric currentflowing in the sense illustrated by the solid-line arrows. Theelectromagnetic wave is therefore propagated in the fundamental mode.Thus, the embodiment of FIG. 4 serves as a reciprocal microwave phaseshifter.

Referring to FIG. (a), a second embodiment of this invention comprises awaveguide 21 and a ferrimagnetic member 22 disposed along thelongitudinal axis of the guide 21. The member 22 is made offerrimagnetic ma terial having rectangular magnetic characteristics intoa generally rectangular prism having four longitudinal holes and aplurality of transverse holes, each hole running through the body of themember 22. Preferably, the longitudinal holes are distributedsymmetrically with respect to the plane passing through the center linesof the broad walls of the guide 21. A set of opposite surfaces of theferrimagnetic member 22 are in contact with the inside surfaces of'thebroad Walls. The embodiment further comprises a set of transverseconductors 23 put through the respective transverse holes and throughthe narrow walls of the waveguide 21. The transverse conductors 23 areconnected together at their respective ends put out of the waveguide 21and are provided with a common D.C. power source 24. The embodimentstill further comprises a set of longitudinal conductors 25 disposedwithin the respective longitudinal holes of the ferrimagnetic member 22.A first subset 25 of the longitudinal conductors 25 are connectedtogether at the outside of the waveguide 21 and connected with one ofthe terminals of a D.C. power source 26. A second subset 25" of thelongitudinal conductors 25 are likewise connected together and broughtinto connection with the other terminal of the power source 26. Switches27 and 28 are provided to supply, upon closure, D.C. control pulses tothe respective sets of conductors 23 and 25.

When the switch 27 is closed to supply a D.C. control pulse to each ofthe transverse conductors 23, the phase shifter is brought into the samestate as the conventional reciprocal phase shifter of FIG. 3(a) with theP connection. When the switch 27 is opened and the switch 28 is insteadclosed to supply a D.C. control pulse to each of the longitudinalconductors 25, the ferrimagnetic member 22 is magnetized in the mannershown in FIG. 5 (b). This state of magnetization is equivalent to thatillustrated in FIG. 2 with the solid-line curves having arrow heads. Thesecond embodiment therefore serves as a reciprocal microwave phaseshifter.

A phase shifter of the construction shown in FIG. 5(a) wherein thedimensions of the broad wall and the narrow wall of the waveguide 21 andof the width (parallel to the broad wall), the height (parallel to thenarrow wall), and the length of the ferri'magnetic member 22 are 12 mm.,5 mm., 6 mm., 5 mm., and 40 mm., respectively, provided a phase shift ofat the 9 gHz. band.

Referring finally to FIGS. 6(a), (b) and (0) there are illustratedfurther embodiments of this invention wherein the paths for guiding theelectromagnetic energy are a circular waveguide, a ridge waveguide, anda pair of strip lines, respectively. The operation does not differ inprinciple from that of the first and the second embodiments.

As is understood from the description, this invention makes it possible,without any complicated demagnetization control but only with simplepulse control, to put a phase shifter into each of two states betweenwhich the maximum phase shift is attained. Furthermore, this inventionraises the overall characteristics because no use is made of themagnetization state which deteriorates the standing wave ratio andincreases the insertion loss.

What is claimed is:

1. A reciprocal microwave phase shifter comprising a path for guidingthe electromagnetic energy, a member of ferrimagnetic material havingrectangular magnetization characteristics and disposed along thelongitudinal axis of said path, a first plurality of conductors disposedtransverse to said longitudinal axis, passing through said ferrimagneticmaterial, and being connected in parallel with one another, a secondplurality of conductors disposed substantially parallel to saidlongitudinal axis and passing through said ferrimagnetic material, andmeans for alternately energizing said first and said second plurality ofconductors.

2. The device as recited in claim 1 wherein said ferrimagnetic materialhas a plurality of longitudinal and transverse bores, with said firstset of transverse conductors being passed through the transverse boresand with a first subset of longitudinal conductors being passed througha first subset of longitudinal bores and a second subset of longitudinalconductors being passed through a second subset of longitudinal bores,with the ferrimagnetic member and the first and second subset oflongitudinal bores located in selective position relative to a planepassing through the longitudinal axis.

3. The device as recited in claim 1 wherein the path for guiding theelectromagnetic energy comprises a rectangular waveguide having a pairof parallel broad walls and a pair of parallel narrow side walls withthe ferrimagnetic material positioned being of rectangular form andpositioned in symmetrical relationship with an axial plane passingthrough the center of the broad walls, said ferrimagnetic material beingprovided with transverse bores aligned along a plane substantiallyparallel to the broad walls with the transverse conductors pass ingthrough the transverse bores and protruding from the narrow side wallsof the waveguide.

4. The device as recited in claim 3 wherein the ferrimagnetic materialis provided with a plurality of longitudinal bores through which thelongitudinal conductors are passed, with first and second subsets oflongitudinal bores arranged in symmetry relative to the axial plane, andwith longitudinal conductors passing through the first subset oflongitudinal bores electrically connected in parallel, and with thelongitudinal conductors passing through the second subset oflongitudinal bores electrically connected in parallel.

5. The device as recited in claim 4 wherein the ferrimagnetic materialis sized to contact the broad walls of the rectangular guide.

6. The device as recited in claim 1 wherein said path of guidingelectromagnetic energy is a cylindrical waveguide.

7. The device as recited in claim 1 wherein said path of guidingelectromagnetic energy is a ridged waveguide.

8. The device as recited in claim 1 wherein the path of guidingelectromagnetic energy is a strip line.

9. A reciprocal microwave phase shifter comprising a path for guidingthe electromagnetic energy, ferrimagnetic material having rectangularmagnetization characteristics and disposed along the longitudinal axisof said path, a first plurality of conductor-s disposed transverse tosaid longitudinal axis, passing through said ferrimagnetic material, asecond plurality of conductors disposed substantially parallel to saidlongitudinal axis and passing through said ferrimagnetic material, meansfor alternately energizing said first and said second plurality ofconductors, said ferrimagnetic material comprising first and secondlongitudinal rectangular shaped ferrimagnetic members havinglongitudinal bores extending therethrough, with said second plurality ofconductors being passed through said longitudinal bores, said first andsecond longitudinal members further being provided with a plurality oftransversely extending bores, with the first and second memberspositioned along the longitudinal axis of the electromagnetic axis withtheir transverse bores in registration to align said first plurality ofconductors substantially transverse to said axis.

10. The device as recited in claim 9 wherein said longitudinal bores arerectangular shaped and wherein said first and second members arepositioned in symmetry relative to a plane including the longitudinalaxis and substantially transverse to the first set of transverseconductors.

11. The device as recited in claim 9 wherein the transverse conductorsare electrically parallel connected to one another.

References Cited UNITED STATES PATENTS 3,332,042 7/1967 Parris 333-3l3,333,214 7/1967 Parris 333-24 3,355,682 11/1967 Taft 333-24.1X3,411,113 11/1968 Heithaus 33324.1

PAUL L. GENSLER, Primary Examiner US. Cl. X.R.

